Process for producing foamed resinous materials



June 27, 1961 B. J. AUERBACH ETAL 2,990,380

PROCESS FOR PRODUCING FOAMED RESINOUS MATERIALS Filed Nov. 4, 1957 INVENTORS l United States Patent 2,99%,380 PROCESS FOR PRODUCING FOAMED 'RESINOUS Bertram J. Auerbach, Brooklyn, N.Y., and. Harry J. Rogers, West Orange, N.J., assignors to Nopco ChemrIcal- Company, Harrison, NJ., a corporation of New ersey Filed Nov. 4, 1957, Ser..N0. 694,215

8 Claims. (Cl. 2602.5)

The present invention relates to novel processes, a step and steps in the processes, as well as apparatus and devices employed for the production of foamed resins, and especially such resins of the polyurethane type which may be either rigid or flexible. In one of its. more specific aspects the invention is directed. to novel processes, a step and steps in the processes, as well as the apparatus and devices for regulating. the cell size of said resins in the course of their preparation.

It is well known in. the art that. foamed polyurethane. resins may be prepared by reacting, either in the. pres ence or absence of catalytic material, one or acombination of. two or more polyisocyanates with one or a com.- bination of two or more organic compounds capable. of reacting withv a polyisocyanate to produce polyurethane resin. Such organic compounds generally have at least two reactive hydrogen atoms. Some examples of such organic compounds which may be employed in the proc! ess of and apparatus of the invention. are polyesters, -poly-. isocyanate-modified polyesters, polyesteramides, polyisocyanate-modified' polyesteramides, alkylene glycols, polyisocyanate-modified alkylene glycol s, polyoxyalkyle ene glycols and polyisocyanate-modified polyoxyalkylene glycols, etc. having free reactive hydrogen atoms, free reactive carboxylic and/or especially hydroxyl groups. Moreover, any organic compound containing at least. two radicals selected from. the class consisting of by; droxyl and carboxyl groups may be employed in the practice of the invention.

Some of the more serious problems. present in the preparation of these foamed materials have been the problems of obtaining uniform cell size and..structure and of obtaining ahigh degreev of reproducibility. These problems are present primarily apparently because of the nature of the reactants and the reaction. mass because of the almost immediate initiation of an exothermic reaction between the reactants upon admixture, the physical characteristics of the mass are, changed and in addition are aifected by other variations of pressure, temperature, viscosity, etc. normally encountered in factory practice. Attempts to obtain improved products; have heretofore been concerned with modes of mixing the components prior to reaction. One such proposalis described in US. Patent No. 2,764,565, Hoppe et al., issued September 25, 1956, in which a catalyst and water are first introduced into the reactants intermity. tently at a high frequency thereby thoroughly mixing all the components prior to reaction. However, this procedure did not bring about complete uniformity or reproducibility to the degree desired by the industry. Accordingly, attempts to modify this procedure were made, first by chemical means, i.e., additives were put in with the raw materials, and later by mechanical means, i.e., coupling a rigid discharge tube with the mixing chamber and removing said tube and replacing it' with a like tube of different diameter. However, these modifications were unsatisfactory for the reasons that the cell structure could be controlled for only short periods of time and it was therefore necessary to shut down theoperation and while in shut-down condition put in extra additives, or else the rigid exit tube was: replaced by a like tube of different size.

"ice

because of the necessity for complete stoppages atbest provided for intermittently controlled proceduresf Moreover, when it was desired to produce such foamed resins having. a different size cell structure, which, sometimes is required-in factory practice, this, demanded a complete. stoppage of operation followed by changing of they exit tube to one of a different diameter.

It is an object of the present invention to provide for processes, steps in such processes as well as apparatus and devices which will assure formation of uniform cell structures having'a predetermined cell size in foamed polyurethane resins.

It is a further object to provide processes, steps in said processes and apparatus and devices which may be, employed for effectively and economically reproducing foamed products of pre-determined cell size and struc ture.

Still another object of the. invention is to provide proc'.- esses and apparatus which may be controlled at will and without stoppage in the production of substantially uniform predetermined cell size resins whereby production a is continuous and the cell size is maintained substantially constant.

' Still. another object of the present invention is to provide processes and apparatus which may be controlled at will in very simple and easy manner to change from the production of foamed material of particular cell size tosuch material of diiferent cell size.

Still another object of the present inventionisto provide'processes and apparatus which may be controlled at will in a very simple and easy manner to change'from the production of foamed material of particular cell size to such material of different cell size and without in-{ terruption of production or stoppage of the apparatus;

Still another object of this invention is to provide processes and apparatus includingan automatically expandable and contractable zone actuable in response to varia tions in pressure therein in the course of passage therethrough of reacting materials and evolved gases to compensate for such variations.

Still another object of the invention is to provide processesand apparatus which may be readily and easily: controlled at will by an operator to initially obtain prep determined cell size resin and to maintain continuousproduction thereof. Still another object of the invention is to provide proc-; esses and apparatus which may be readily and easily controlled at will by an operator to initially obtain predea termined cell size resin and to maintain continuous pro-. duction thereof despite normal variations encountered. in factory production of such resins.

Still'another object of this invention is toprovide processes. and apparatus including an automatically expandable and contractable zone actuable in response to variations in pressure therein in the course of passage therethrough of reacting materials and evolved gases tocompensatefor such variations, said processes and apparatus; being readily and easily controlled at will by an operator to obtain initially predetermined cell size resin and to: maintain continuously the production of such resin.

Reference is now made to the accompanying drawingswhich illustrate a novel apparatus and a novel device Hence, these modifications a FIG. 1 illustrates a device for storing, mixing, reacting the several components used, in preparing foamed polyurethane. resins, said device including our novel dia phragm valve,

- FIG. 2 is an enlarged view of a portion of the valve 3 of FIGURE land showing the valve and a mixing head in a vertical cross sectional'view.

FIG. 3 is a cross sectional'viewtaken on of 7 FIG. 2. FIG. 4 is a view taken on line IV-IV of FIGJZ'.

Referenceis now made to FIG. 1, which discloses the Hoppe et al., apparatus made part hereof, in combina-. tion with certain other elements thereby providing novel combinations of this invention. The .Hoppe et a1. apparatus comprises essentially a storage tank 2 carrying a quantity of polyisocyanate, tank 6 carrying a quantity of organic material capable'of reacting with the polyiso cyanate'to produce polyurethane resin, and storage tank Io' c'arr'ying aq'uantity of a'catalyst; The organic com pound may becontinuouslyfed from tank 6 into a mixer 14 bylfthe action of a pump -8, while the polyisocyanate line nI-m 4 and 30. In assembled condition, there is provided a restricted passageway or zone 25 by the face of projection 26 and the inner face of diaphragm 28, and the zone 25 communicates with inlet and outlet openings in body 30 to create a Venturi tube. The body 30 and the. bonnet 27 are rigid and composedof cast-iron, steel or the like.

i The diaphragm 28 in this specific embodiment in a flexible imperforate material and preferably such a material which is resilient or elastic, as for example, a rubbery material, which in one of its forms may be naturalor synthetic rubber, and in all cases, ofcourse, is impervious and inert with respect to the materials contacting it. In the particular embodiment shown diaphragm .28

from tank 2 is simultaneously injected intermittently into s'aid mixer 14 by means of pu'mp4 and. the catalyst is fed from tank and is' injected intermittently into said mixer .14 by. pump 12. .Asshown in FIG. 2, the miXer 14con1pris es'a barrel'15, fed through three inlets 18,

21Qfor the introduction of said three components the flexible rubber tube 34 is connected to a stationary via flexible hose from the separate storage tanks 2, 6 and reassi n agitator 16 to aid in the mixingof such com-l ponents delivered thereto. The mixture of such componentsgwhilebeing constantly agitated by the stirrer 16, is pressure fed downwardly through the central opening in the tapered outlet cap 17. 7,

According to this invention, there is coupled to said outlet cap 17, means for providing a restricted passage way communicating with said chamber-15 and with material fed from the mixer 14 passes through said restricted passageway and then throughsaid discharge passageway. In the course of the mixing of the reactants in mixer 14 and the travel thereofinto and through said restricted passageway and into and through said discharge passageway, reaction between the reactants. is initiated and occurs and gaseous CO is evolved, andthe resultant gaseous C0 laden liquid mass isdischarged into a"v conveyor wherein it sets into a foamed resin.

means for providing adischarge passageway wherebythe is composed of elastic or resilient butyl rubber of the type and thickness currently employed as inner tubes for tires. The bonnet 27 has a central opening therethrough. Mounted in said central opening of said bonnet andexg tending therefrom is a flexible rubber tube'of considerable lengthvof 1 0to 50 ft. or more. Said tube 34 communi- Cities with a chamber 29 provided by the bonnet 27 and the outside surface of diaphragm 28. The other end .of

pressure gauge 36," which is attached to a fluid pressure line including therein a stationary control valve 38 and connected to a source (not shown) of fluid under pressure. The mixer 14, together with the novel valve 24, connector 22. and discharge tube 32 may be reciprocated back and forth in unison without disturbing the gauge 36 or the valve 38, which are stationary, due to the use of the long flexible hose 34, so that the position of the valve 38 and the gauge 36 are always maintained in fixed position close to each other as shown so that the operator may, when he desires, actuate the valve 38 and view gage 36 without stoppage of the apparatus. 7 1

The fluid under pressure'supplied to the chamber 29 is generally air under pressure, although other gases or Said restricted passageway or zone. is formed by hollow 5 means, at least a portion of which is movable relative to another. portion thereof whereby the size of said passage-v way onzone'may be increased or decreased. :Associated with said hollow.means is adjustablemeans capableof acting upon said movable portion formoving said movable portion at will to increase or decrease the size. or cross sectional area of 'said restricted passageway. or zone. Said-portion of. said means which is movablewith respect to another portion thereof may be of a great variety or different compositions, structures, shapesand forms.

As shown in FIG. 2, a novel valve 24 is coupled with said mixing chamber 14 through a conduit or pipe 22 to provide a novel combination of this invention. Said valve 24 comprises a hollow body 30 including 'a central Due to the particular fluid pressure employed and read:

able on thefgauge 36, the operator may at will vary the size or cross sectional area of the restricted passageway or zone 25.

The operation of the apparatus, including novel combinations and novel devices of the present invention capable of efiecting the novel processes and steps in the processes of the present invention, is as follows: The mixture of components from mixing chamber 14 is fed downwardly therefrom into and through conduit 22, and

' into and through the upper or inlet opening of valve 24,

then into and through the restricted zone or passageway 25,- then into and through the lower or exit passageway of valve 24, and into and through the discharge tube 32 and from there the resultant liquid reaction mass, containing gaseous particles liberated in the course of reaction, passes projection 26 whose inner face terminates a small dis-,;

tanceinwardly from a face thereof which acts as aseat for a diaphragm 28. The body 30 has a pair of passa e; ways, withtheupper one as shown communicating with the inlet tube 22 and the lower one as shown commu-..

nicating with a discharge tube 32. The diaphragm 2'8 extends across said face of'body 30 and a bonnet '27 is disposed on theother side of said diaphragmf A plu r'ality' of bolts secure together these elements 27, 28

into moving pans or other convenient means wherein the liquid becomes converted from the liquid state into solid foamed resin. 7 I

. If the cell size of the foamed resin produced is not that which is desired, While the process continues, the operator merely actuates the control valve 38 to change the fluid pressure exerted against the outside of the diaphragm 28 to change the size of the restricted zoneor opening 25 to produce solid foamed resin of the desired cell size.

- 'In the course of the reactants in the mixer 14 being mixed together with the aid of the rotating stirrer 16 and thereafter in'the course of travel of said mix through thevarious passages, reaction is initiated and continues. together with evolutionof 'gaseous CO and in addition even after the discharge of the CO laden'liquid reaction mass ffomdhe discharge pipe $2 into a container, reac- 5 tioncontinues whereupon the massis converted. from; the. liquid. state so a solid. foamed resin: Asthe reaction mass. passes into. and through the restricted. passageway or zone 25, due to varying or fluctuating conditionsten countered in normal. factory, practice, there be: efiected in said mass, which is continuing. to react. togetherwith evolution of CO gas, variations inpr essure 'againstthe interior face of said diaphragm 28. Due to the. resiliency. or elasticity of the diaphragm,28:per se, or due to its flexibility and resiliency imparted thereto by virtue of the: air cushion therebehind, the diaphragm 28 automatically moves back. and forth in response to such variations in pressure therein as said mixture reacts and. evolves CO in. its passage therethrough, thereby acting as means which automatically expands and contracts .in response tosuch variations in pressure which are relatively small and diflicult to measure. In fact, said diaphragm 28 acting together with the inner face ofprojection 26 provides a restricted passageway or zone which is capable ,of automatically expanding and contracting invresponse to such pressure variations. Consequently, due to such automatic expansion and contraction of zone 25, due to such pressure variations, it is possible to obtaingreater uniformity of cell sizeinthefinishedproduct. Said auto matically expandable and contractable zone 25,, responsive to such pressure variations, in certain instances will compensate therefor, thereby providing a self compensator or self-regulator whereby substantially uniform cell structure may be continuuosly obtained. Thezadvantage of this embodiment is that the operator is called. upon only to adjust for greater variations which he may correct by manipulating valve 38.

When, as sometimes occurs, the variations in conditions are such as not to be effectively compensated for by the diaphragm 28 per se, the operator, observing in the course of a run that the cell size has changed so as to be very near a limit or to be without the desired limits thereof, he, without any stoppage whatever of the apparatus, merely adjusts the valve 38 to either decrease or increase the air pressure against the outside of the diaphragm 28 to the desired degree and as conditions demand to decrease or increase the size or cross section of zone 25, to produce solid foamed resin that meets the specification. When it is desired to produce foamed resin of a different cell size than that being produced, even in this instance, neither the operation. nor the apparatus need be stopped. All that the operator need do is merely to actuate the control valve 38, whereby the pressure of the fluid against the outside of the diaphragm 28 is either increased or decreased to reduce or increase the size of: the restricted passageway or zone 25, as the case may be, to produce foamed resin of the now desired cell size.

The combination, as described and as shown in the drawings, aflfords devices, apparatus and methods for continuously producing plastic foamed res-ins of preselected uniform cell size and also atfords devices, apparatus and processes which may be readily and easily controlled for continuous operation and at the same time maintaining substantial uniformity of cell size, and in addition, even while the operation is continuous, the apparatus is capable of change to produce foamed resin of a particular cell size for a certain period, and then when desired, without any stoppage whatever, continuously produce foamed resins of uniform and other desired preselected cell size.

The. theory of operation we believe to be as follows: The valve 24, is set by the setting of the control valve 38 and: the magnitude of fluid pressure in bonnet 29 is evidenced by reading on gage 36. In other words, a con.- stant. air pressure, whose magnitude may be ascertained by reading. the gage 36, is exerted upon that side of dia: phragm 28 covered by the bonnet 29. In view of the constriction. of passageway-2511sdefined by projection 26 and diaphragm 28, the volume available for the flow of as es the reactionmass is decreased, the, velqcityds increased andutliefpressure is decrea d ence. the11res .re nv pass ew y iww s t atini i a amber I5, whereupqnmi'crosizedl bubblesor particles of CD gasi'ntlre'reactio'fn, mass may increase more rapidly and:

more uniformly th'anfiif' they were allowed to grow with,

no control. .Thusbyregulatingthe control valve 38 pressure. against diaphragm 28. is.v controlledv so that, the air pressure on diaphragm. 2,8 andlthe volume or. cross sectional area of zon e Z5 may be maintained-fairlyv constant in order toproduce afoamed resin having a, predeterminedcellsizeI v I H Although. the air pressure against diaphragm 28; is maintained fairly. constant andlis of a magnitude, set, and d'eterminedby the control, valve 38, the pressure, exerted against the other lside'of the diaphragm 28" tends to vary due to, normal; factory encountered, variations in pressure of the reaction material passingthrough zone 25 and sometimes such changes, in the absence of such flexible diaphragm would result in the ultimate production, of

irregular. andnon-unifo'rmand sometimes too finelrcell structure in the, foamed. resin produced. However, due to the faetthat the diaphragm 28 is flexible and'is per se resilient or..,resilie' nt because of, the. air pressure thereaga ns't the valve 24 has the, unexpected and; surprising function of acting as aself-compensator or self-regulator actuable in.v response: to pressure variations in. zone 25 whereby the zone automatically expands and contracts and apparently the diaphragm 28fmovesback andforth' frequently to compensate for frequent, variations, in the pressure of said reaction mass passing through zone 25 sothatthe cell size of. the ultimate foamedresinproduced ismaintained substantially unifomnand between certain fixed limits.

If, for instance, the volume of thereaction mass enter-. ing saidzone 25 ,per. unitof time is decreased, the velocity and pressure of the masspassingtherethrough are respectively increased and decreased. This is accomplished by diaphragm, 2 8, under the greater constant pressure exerted from chamber 29 moving; towards. projection 26.thereby, narrowing zone 25 at this point. reduction in size of zone 25. causes the velocity of the. mass to increase and the pressure to decrease thereby compensating for the fluctuation. I

Conversely, if for instance, the. volumeof. such. mass entering the zone 25' per unit of timeshould increase, the pressure therein would decrease thereby resulting in too rapidcell growth. However, the resultant pressure -in zone 25 due to build up of material therein is exerted upon the diaphragm 28 and will move diaphragm, 23 thereby enlarging the: size of the zone- 25, and as. a consequence of such enlargement or increase in-cross sectional area ofsaid zone, the velocity of the mass passing therethrough is decreased and the. pressure thereof increased, thereby restricting the cell growth and compensating for such fluctuation.

Of. course, as before stated, when, as sometimes happens, the variation in conditions; is so great or of such character as to be incapable of being corrected by said self-compensator or self-regulator, the operator, without any stoppage whatever, merely actuates the valves 38%" to either increase or decrease the air pressure on the bonnet side of diaphragm 28to decrease or increase thesize .or cross sectional area of zone25-sothatfoamed resin ofthe desired cell size is obtained. 2

Our novel process and apparatus have: been described as used with the process of, as well as the apparatus. disk closed in, the aforementioned Hoppe et. patent. It is, of course, understood that our process is not limited to this. particular process of mixing the: components nor to the. apparatus disclosed by. Hoppe, et. a1. forcarrying. out such mixing. Neither is our process limited. to theuparticular apparatus described herein, nor, on the other. hand, is our novel apparatus useful solely in this PI QQSS.

which comprises a polyisocyanate and'polyester orpolyether in a fine state of subdivision and at a pressure. higher than that of the reaction mixture. This mixing procedure. is carried out before reaction occurs. According to one embodiment of their invention, the catalyst mixture is introduced or injected intermittently intoafcontinuous stream of poly'isoc'yanate and polyester or polyether; which stream is advanced by means such as agear pump system. .To insure adequate penetration of the activator mixture into the reaction mixture, the intermittent feed enters through a nozzle or" nozzles at'a relativeIyhigh pressure and frequency. .In a preferred em: bodiment the two reaction components of the reaction inixture; namely at least one diisocyanate and at least one. polyester containing hydroxyl groups, are conveyed separately to a mixing device into which'they are injected under" 'prelssure through separate nozzles or acommon nozzlev and the catalyst mixture is either conveyed separately to the reaction device and injected into it under pressure through a separate nozzle or a common mixing nozzle. Ina'nother embodiment the catalyst may be con yeye'd to'the mixing device in admixture with the polyeste1: sa idfmixture being injected intermittently into the mixer either through a common mixing nozzle with the isocyanate or through a separate nozzle.

; vInthe practice of Hoppe et al. in its preferred form, the components employed in the manufacture of the resin are forced .into. acommon mixing device by means of pumps. One of .the pumps operates continuously while the other pumps operateintermittently. All of the pumps areconnected to the mixing device into which one component is introduced continuously while the catalyst or preferably the catalyst and .the polyisocyanate are introduced intermittently.' Thecomponents conveyed by the pumps are introduced by means of nozzles into the reactionior device which has outlet means through whichthe final mixture is discharged in the liquid state. "I husthe apparatus of Hoppe et al. comprises, in combination, an enclosed, mixer andmeans through which the components (i.e., polyester or polyether containing free hydroxyl groupspolyisocyanate and catalyst) used in the manufacture of the resin are brought together in said mixer, at least one o fsaid means comprising an injector operating at apressure substantially higher that that in mixer, and outlet means through which the final uniform-mixture of components is discharged in the liquid state.

As a specific embodiment of Hoppe et al., the apparatusmay comsprise in combination an enclosed mixer, means to effect a continuous flow of initial materials, i.e., polyisocyanate and polyester or a polyisocyanate modified polyester or polyisocyanate polyether mixture to the mixer, means for feeding the catalyst and/or polyisocy anate and'means for intermittently injecting at high frequency the catalyst and/or polyisocyanate in precise quantities into a'continu'ous stream of the initial materials by means of at least one injection nozzle. 'Theinitial material or materials and the catalyst are stored in tanks and conveyed to'the mixing device by meansof pumps which operate continuously and intermittently as indicated above. The mixing device may contain separate comparuments or chambers for injection of the components and'mixing or it may be constructed so that both injection and mixing are carried out in a single compartment, In the single chamber mixer, the three components, i.e., the polyisocyanate, polyester and catalyst are preferably conveyed by theirrespective pumps through parate nozzles into themixer which preferably contains .gmanslar a provide for the introduction of'a catalyst'into a reaction sauna as theofresin desired. Normally the is in the range of 0.5 to 25 seconds, although longerori even shorter mixing periods may'in some cases'bedef sirable. r j Concerning the introduction of the catalyst or a of the catalyst plus isocyanate, .a relatively high velocity is used so that it will adequately penetrate the'high yiscosity polyester and form a uniform mixture. This is efiectedby means of art-injection nozzle through which the catalyst or catalyst-isocyanate mixture is introduced at a pressure in the range of about 1200 p.s.i. to about-5250f p.s.i. However, Hoppe et a1. contemplate the'use of iii-f jection-pressures' which are higher and preferably subs'tantially higher than the back pressurewithinthe-re action or mixing device. Normally,'athe backpressure; within the device is of the order of from 4-5 p.s.i. to '75 p.s.i. depending upon the viscosity of the material and the size of the discharge outlet. In'tbe case of low viscosity material'sjlthe back pressure may drop to as] low as '17 p.s.i., buf't'with more highly viscous materials, it may'in crease to much higher values than are normally encouhtered. As to the frequency of the injection of the catalyst or catalyst plus isocyanat'e, an injection rate of about ioto10,000 or preferably about 2,000 to 10,000 injections pet-"minute are carriedout. However, we havefound that even a continuous injection'may be used instead-so long as the'pressure of the injected component is substan-' tially in excess of the pressure of the other component and thorough mixing of the components is attained.

The-following examples are given merely to illustrate specific methods and apparatus embodying the invention which are not to be taken by wayof limitation:

EXAMPLE I A polyester was first prepared in the followingmannerz' 83 mols of diethylene glycol, 76 mols of adipic acid, and 1.34 mols of tn'methylol propane were mixed together and heated vat an ambient temperature of from 150 to 440 F. for approximately 4 hours. The acid number of the resultingpolyester was 10 The hydroxyl number was between 50 and 55. The water content was 0.1%

by weight of the polyester.

tionsand character of the components employed as well Tank 6 was then charged with this polyester while tank 2 was charged with m-toluene di-isocyanate and tankloj was charged with a catalyst mixture comprising 3.0 parts by weight of N-eth yl morpholine, 1.0 part by weight of A-3 (an aliphatic amine-ethylene oxide condensate prepared by'Mobay Chemical Company), 1.5 parts by weight of Witco 77-86 (an arylethy-lene oxide condensate prepared by Witco Chemical Company) and 3.6 parts by weight of water. Tanks 2 and 10 were maintained at room temperature while tank 6 was maintained at a ternperature between 60 and F. a y Control valve 38 was adjusted so that air pressure of 10 p.s.i. was maintained upon diaphragm 28. V The toluene di-isocyanate was pumped by. pump 4 at a rate of 4 pounds per minute, thecatalyst mixture was pumped by pump 12 at a rateof 1.5 pounds per minute and the polyester was pumped by pump 8 at a rate of. 10 pounds per minute to mixer 14. The polyester was pumped continuously while the diisocyanate and catalyst were injected into mixer 14 at a rate of 7200 injections per minute and 2400 injections per minute respectively. The above reaction mixture was thoroughly mixed in mixer 14 for about 1.5 seconds. The. ratio of the components as admixed in the mixer was 15.5 pounds polyester, 7.25 pounds isocyanate, and 1.5 pounds cata-. lyst. Thereafter the mixture which had begun to react and to evolve carbon dioxide was discharged from mixer 14 through pipe 22 valve 24, and pipe 32 from which a liquid, gaseous CO laden, reaction mass was finally dis-' charged into a movable conveyor (not shown) and wherein it was converted into a solid foamed resin. While the reaction mass traveled through passage or zone 25 the pressure in passage 25 was maintained at a substantiallyconstant value based on the original adjustment-of; valve EXAMPLE II Tank 6 was charged with the polyester of Example I while tank 2 was charged with m-toluene diisocyanate and tank -10 charged with a catalyst mixture containing 1.8 parts by weight n-ethyl morpholine, 2.2 parts by weight n-coco morpholine, 5.3 parts by weight of emulsiher and 2.1 parts by weight water. Tanks 2 and 10 were maintained at room temperature while tank 6fwas maintained at a temperature between 60' and 70 F;

Control valve 38' was adjusted so that air pressure of psi. was maintained upon discharge 28.

The toluene diisocyanate was pumped by pump 4 at a rate of 3.2 pounds per minute, the catalyst mixture was pumped by pump 12 at a rate of 0.89 pound per. minute. while the polyester was pumped by pump 8' at a rate of 10 pounds per minute to mixer 14. The polyester was pumped continuously while the diisocyanate and catalyst were injected into mixer 14' at a rate of 73200 injections per minute and 1200 injections per minute respectively. The above reaction mass was thoroughly mixed in mixer 14 for about 1.5 seconds. The weight ratio of the. components as admixed'in. the mixer was 1100 parts polyester, 32 parts isocyanate and 8.9 parts catalyst. Thereafter the mixture which had begun to react and to evolve carbon dioxide was discharged from mixer 1f'4 through pipe 22; valve 24, and discharge tube 32 from which. a liquid, gaseous CO laden, reaction mass was finally discharged into a moving conveyor ("not shown) wherein it was converted into a solid foamed resin. While the reaction mass traveled through passage 25, the external pressure in passage 25'Wasmaintained at a substantially constant value based on the original ad? justment of valve 38 and due to such compensatory movement of diaphragm 28.both towards and away from projection 26 due to variations in pressure on the other side of and capable of being automatically corrected". by said diaphragm in the course of the passage of said reaction mass through said zone, uniformity of cell size was automatically maintained. The resulting] flexible foamed resin had a regular and uniform cell. structure of approximately of an inch in diameter.. The density of the product was 3 pounds per cubic foot.

EXAMPLE III Tank 6 was charged with the polyester of Example I while tank 2' was charged with m-toluene diisocyanate and tank 10 charged with a catalyst mixture containing 1.5 partsbyweight of m-methyl morpholine, 211' parts by weight n-coco morpholine, 3.9 parts by weight emulsifier andlLZ parts by weight water. Tanks 2 and 10' were maintained at room: temperature while tank 6 was maintained'at atemperature'between 60 and 70 Fi Control valve 38 was adjusted so that a pressure of 7 psi. was maintained upon diaphragm 28.

The toluene diisocyanate was pumped by pump 4 at a rate of 2.3 pounds per minute, the catalyst mixture was pumped by pump 12 at a rate of 0.62 pound per minute while the polyester was pumped by pump 8 at a rate of '10 pounds per minute to mixer 14. The polyester was pumped continuously while the diisocyanate and catalyst were injected intomixer 14 at a rate of 7,200 and L200 injections per minute respectively. The above reaction components were thoroughly mixed in mixer 14 about 1.5 seconds. The ratio of components as admixed in the mixer was 100 parts by weight polyester, 23

parts byv weight isocyanate and.6:2 partsv by weight. cata; lyst. Thereafter the mixture which had. beguntoreajctj and. to evol-ve carbon dioxidewas. dischargedlr oni mixer 14-;through-pipe 22;, valve 24 and pip'ef32, from. which a. liquid; gaseous. CO laden, reaction masswas. finally. di'jsf charged into-a moving.. con-veyor (notshown) wherein it was convertedint'o a solid foamedresin. Whilethe re; action. mass traveledthrough passage 25, the external pressure in=passage 25.was maintained at a substantially constantvaluebasedon. the or-iginaLadjustment' of valve 38 and. due to compensatorylmov'ement of diaphragm 28 both towards and away from. projection 26 due to variai tions in pressure on the other side of and? capable of being=automatically correctedby said diaphragmfin the course'of the passage of said reaction mass through said zone, uniformity of. cell. size was automatically. main; tained. The resulting. flexible foamed resin had a jregu= lar and uniform. cell structure of approximately, pf an inch in diameter. The. density of'the product was 5 pounds per cubic footy f In the preceding examples, the m-t'ol'uene diisocyanate comprised the 2,4 and the 2,6" isomers in an :20 parts by weight ratio. 1 1

It-must be appreciated that the operating ranges of the air pressuremaintained. upondiaphragm. 28 will; vary depending uponthe sizeof the valve. anddiaphragnig ithe material of the diaphragm. a nd. the rate of flow of the materials through it. In general; when a inch diaphragm' valveusi-ng a /32 ll'lGh' butyl rubber diaphragnizis employed, thepressure-maintained upon the diaphragm may vary over wide limits, and may vary from 0 to 50 p.s.1.

Ingeneral; the present invention is applicable to the production of" foamed plastics, bot-h rigid and flexible, using any' of-- the previously referred to organic compounds having atleast two reactable hydrogen atoms and-;capable of. reacting-witha; polyisocyanate... .In one specific embodiment, theinvention may be practiced. using. apolyester: having an acid number of from-about 0.5. to about- 8'0. Asv used throughout. the specification and. intheclaims, the: expression. .polyester includesr any product produced by the. reaction. of. a. polyhydricfalco; hol. or. mixtures thereof. and. a. polybasic .acid' or, mixtures thereof- The. polyestersthatare used. are preparedf'rom apolyhydric alcohol-polybasic.acidlmixturein which the ratioofhydroxyhgroups to carboxy]. groups is withinfthe range of fromabout- 3 hydroxyls: 1' carboxyl to 4. hydroxyls; 5. carboxyls. Thus, for example, polyesters which are. Well. suited, for use can be produced by reacting polybasic acids or mixtures thereof, such as succinic acid, adipi'cacid, sebacic acid, i'sosebaci'c acid, azelai'c acid, citric acid, lactic acid, phthalic acid, terephthalic acid, etc., or other similar ester-formingcompounds, such as, phthalic anhyd'ride, maleic anhydride, etc. with ap'-' propriate quantities or polyhydric alcohols, such asethyl ene 'gl'ycoL. diethylene glycol, triethylene glycol, propyl ene glycol, 1,4 butylene glycol, glycerol, trim'ethylbl propane, pent'aerythritol, mannitol', sorbitol, etc., as Well as mixtures thereof. Moreover, in addition to such poly esters, the improved. plastic products of the invention canbe produced using any of the so-called' modified'polyesters. of the art. Modified'polyesters are produced by adding, agents, such as, oleic acid; castor oil; linseed oil; resin copal, rosin, etc. to the .polybasic acid-poly hydric: alcohol'formul'ation prior to converting same, by appropriate means, into the desired polyester.

The method. employed in producing. thepolyesters themselves used preparing, our novel foamed. plastic products is not a part of, and, hence, does not limit the scope of, the invention. In. general, polyester compositionsifully suited for use can be prepared by any of the procedures-well known; to the art. As indicated heretofore, it isapreferred; thatathey be preparedfrom such= quan.-' tities! ofi polybasic: acids. and. pol-yhydric alcohols: as; provide a: ratiooihydroxyk groups. to carboxyl groups in '11 the reaction mixture which the range of from about 3 hydroxyls: l-carboxyl to 4-'hydroxyls: -5 carboxyls. Moreover, while in? its broadest embodiment, the invention'contemplates the use of apolyester having anfacid number the ranged from about 0.5 to about 80,. the use of a polyester'having an-acid number a: from about 0.5 to about 25 has been found to-bring about particularlyoutstanding" results. Furthermore, in the preferred practice of the invention, the polyester used have a watercontent of from about 0.1% to about 5.0% by weight. The dollowing examples are formulations employed in producing a few'of the polyesters that be'used.' When suitably' adjusted toan acid number within the-range of from about 0.5'to about 80 and, pref ramg nhen adjustedito a. water content. of from about 0.1%v to about 5.0% by weight, any or the following polyesters can be used in producing some of the prodseeps invention with equally outstanding results. It should be understood, however, that in setting'fonh ese specific formulations, we do 'not intend to restrict invention to the use thereof.

Formula A Y .1: MQ1S Glycerol s 4 Adipic acid V v 7 3 l I 7 Formula B Trimethylol propane 3 Phthalic anhydride 2 Formul'aC v Glycerol" f V p l Phthalic anhydride e p I 1.5 Oleic acid 0.5

As'has been disclosed above, polyester resins employed inproducing the foamed-plastic products have a water content within the range" of from 0.1% to 5.0% by weight; However, the important consideration is not the" presence. of the small quantity of water in the resin itself. f'Rather, it is the presence of the water in the reaction system. It is well known in the art that, although foamed products can be obtained by the reaction of a polyester resin and *a polyisocyanate in the absence of Water, the presence of small quantities of water in the reaction system contributes greatly to the production of plastic products of decreased density." Use of a water- 'containing polyester resin is merely a simple expedient for insuring the presence of thatquantity of water. Thus, since the manner inwhich water is incorporated into'the reaction system is of no importance whatsoever. to the operability of the invention, its presence can be provided {for in any one of several ways. The resin to be used can be produced in'such a manner that it will contain the uantity of water required by the system for completely satisfactory results or 'water can be incorporated by suitable means into the resin at some time prior to its use. In addition, the required quantity of water can be incorporated into the reaction mixture in combination with a non-ionic wetting agent or by use of one or more metallic salt hydrates in the manner disclosed in U.S. Patent 2,577,279. Effective non-ionic wetting agents include, among othersjalkylated phenoxy polyethoxy ethanols, polyoxyalkylene derivatives of hexitol anhydride partial long chain fatty acid esters and watebsoluble hydroxylated resins. The'mtallic hydrate'salts which are similarly. effective includesodium acetate trihydrate, manganouschloride tetrahydrate, cupric nitrate hexahydrate, and calcium chloride hexahydrate. I The polyethers wmen we may use comprise e.g., polyethylene glycols of molecular weight of 1,000; 2,000 and up to- 4,000, polypropylene glycols of the samemolecul-ar weight" and graft polymermixtures ofpolyethylene and 'polypropylene'glycols,having a molecular weight of 2,000 to 4,000. Ethylene oxide and propylene oxide. conden;

sates with amines, glycerine, hexane triol, trimethylol propane, etc., having molecular weights of 2,000 to 4,000 are also useful. ,The polyester or polyether employed is reacted with; a composition containing more than one isocyanate group and referred to generically as a polyisocyanate. In-' cluded within this category are various polyisocyanate compounds, and mixtures thereof, blends containing a polyisocyanate and one or more high molecular weight thermoplastic film-forming additives and polyisocyanate addition products. The polyisocyanate reactant can be replaced either in whole or in part, by a polyisothiocyanatecompp'und. Products having excellent properties and characteristics can be produced by reacting the polyester with a polyisocyanate compound such as metatoluene diisocyanate or with an addition product thereof. Other useful polyisocyanates are other isomers of toluene diisocyanate, e.g., p-toluene diisocyanate, triphenyl diisocyanate, diphenylmethane diisocyanate, ethylene diisocyanate, rm and p-phenylene diisocyanate, propylene 1,2- diisocyanate, and triphenylmethane triisocyanate.

. The polyisocyanate addition products that may be used are compositions such as are disclosed in U.S. Patent 2,602,783. These are products produced by' reacting a polyisocyanate with a compound, or with a mixture of compounds, having more than one functional group of radical, each of which groups or radicals contains at least one labile hydrogen atom capable of reacting with the'polyisocyanate compound by addition polymerization. I Examples'of compounds containing such reactive groups and radicals are: 1) polyfunctional aliphatic alcohols, such as 2-methyl-2,4-pentanediol; 1,4-hexanediol; l,5-pentanediol; ethylene glycol; diethylene glycol; etc., (2) polyfunctional phenols, such as resorcinol; pyrocate chol; pyrogallol; etc., (3) bifunctional metal soaps, such as, aluminum monostearate, aluminum monooleate, alumonopalmitate, bismuth monostearate, etc. Furthermore, addition products of the type produced byreacting a polyisocyanate compound wtih a polyfunctional amino alcohol such as Z-amino l-butanol, LB-amino 2- propanoL a polyfunctional aliphatic or aromatic amine or a polyfunctional thioglycol can be used. A very useful polyisocyanate is m-tolene diisocyanate containing 4% by weight of ethyl cellulose. Prepolymers may likewise be used in the reaction mix ture. These are reaction products of polyisocyanates with polyethers or polyesters and have present isocyanate' groups and hydroxyl groups in a ratio of from 1.05 (NCO) :1 (0H) to 4(NCO) :1(0H).

Our embodiments have been carried out with the employment of catalysts for the reaction between the polyester and polyisocyanate since we have described the procedure of Hoppe et al., supra. However, use of ,cata lysts is optional i.e., polyesters or polyethers and polyisocyanates may be mixed and reacted together in their absence and such a reaction may be handled according to our process for regulating cell structure. Should catalysts' be used such may be, for instance, selected from the following materials N-alkylmorpholines, e.g., 'N-methyl morpholinc, N-ethyl morpholine, tertiary amines, e.g., trimethyl amine, triethyl amine, dimethyl hexahydroaniline, diethyl hexahydroaniline, piperazine and derivatives of piperazme.

We have demonstrated our novel process, novel device and novel apparatus for controlling cell structure in conjunction with a mixing procedure an example of which procedure is that described by Hoppe et al., supra and have employed therewith adjustable presettable and selfregul-ating means, example of which is the novel type of diaphragm valve 24 together with the adjustable air pressure to provide various combinations. It is understood that other mixing procedures may be used in place of the Hoppe et al. procedure and other mechanical means may be used in our processtov regulate or control the size and/or uniformityof cell formation. .For instanemour process may be accomplished by the use ofanyi adjustable meanswhich can vary flow rates and pressuretlirougliia;

delivery pipe. Such means may be activated by gas, hy'- draulic, mechanical, electrical or electronicmeans."

Also, our novel valve maybe used in other processes besides our process for controlling uniformity of celP structure. For instance, our valve may be successfully employed to maintain iiow pressures of fluids, il'ez, liquids and gases, at a constant rate despite fluctuations of d'elivery pressures and delivery rates. It may also b'e used to'control flow pressures of mixtures of fluids e.-g'., mixtures of liquids, mixtures of gases, or mixtures of liquids and gases in spite of variations in delivery pressures or rates. Solids may also be present in. such fluidsor iluid mixtures. The valve need be only preset andwill maina constant flow pressure continuously and automati- Callywithout further manipulation.

It is to be understood that the following claims are intended to cover all the generic and specific features of the invention herein described, and all statementsof, thescope of the invention, which as a matterof"language might be said-to fall therebetween.

We claim:

1. The method for producing foamed plastic material comprising mixing together an organic polyisocyanate and an organic compound having at least two? re'actabl'e hydrogen atoms and capable of reactingswith said polyisocyanate with the evolution of carbon dioxide. gas for the production of said foamed plastic material and passing the resulting reacting mass accompanied by the evolutionof carbon dioxide gasintoand through a pressure responsive restricted zone wherein reaction accompanied by the evolution of carbon dioxide gas continues to occur, said zone having a pressure responsive movable member, which member expands and contracts said zone in response to pressure variations exerted therein by successive portions of said reacting mass passing through said zone thereby aiding in maintaining substantially uniform cell size in the ultimate material produced.

2. The method for producing foamed plastic material comprising mixing together an organic polyisocyanate and an organic compound having at least two reactable hydrogen atoms and capable of reacting with said polyisocyanate with the evolution of carbon dioxide gas, for the production of said foamed plastic material, and while a pressure responsive restricted zone is maintained under substantially constant external pressure, passing the resulting reacting mass through said pressure responsive restricted zone wherein reaction occurs and carbon dioxide gas is evolved during the passage of said reacting mass therethrough, said zone having a pressure responsive movable member, which member expands and contacts said zone in response to pressure variations exerted therein by said reacting mass during the passage of said reacting mass therethrough thereby to aid in effecting substantially uniform cell sizein the foamed plastic material ultimately procedured and presetting the cross-sectional area of said zone by varying the magnitude of said substantially constant pressure applied externally to said zone while said reacting mass is passing through said zone thereby to effect a change in the cell size of the foamed plastic material ultimately produced.

3. In a method for continuously obtaining foamed polyurethane plastic material, the steps comprising, in the course of reaction of a mass comprising an organic polyisocyanate and an organic compound having at least two reactable hydrogen atoms and capable of reacting with said polyisocyanate and accompanied by carbon dioxide gas evolution and ultimate conversion of said reaction mass into a foamed polyurethane plastic organic reaction material, and while a pressure responsive restricted zone is maintained under substantially constant external pressure, continuously passing said reacting mass accompanied by carbon dioxide gas evolution through said pressure responsive restricted zone having a pressure responsive movable member, which member expands and contracts the cross-sectionalareaof said zone'in responseto variations in pressure exerted therein by said reacting: massaccompanied by carbon dioxide gas evolution in the-continuous p-assage thereof into and through said zone, thereby to aid in effecting substantially uniform cell size in the foamed plastic material ultimately produced and presetting the cross sectional area of said zone by varying the magnitude of said pressure applied externally to said zone while said reacting mass is passing therethrough thereby toeffect a change the cell size oft-he foamed plastic material ultimately produced, said cross secti'on'al area being'transverse to thepath of travel of said reactingmasstlirough said zone.

4% In a method f'or continuously obtaining foamed polyurethane plastic material" the steps" comprisin in the -courseof' reactionofamass comprising; an organic polyis'o'cyanate and" an organic compound. having at least two reactable hydrogen atoms and capable of reacting with said polyisocyarrate and accompanied by carbon dioxidega's evolutionand ultimate conversion of said reaction mass intoa foamed polyurethaneplastic organic reaction material, and while a pressure responsive restrictedzoneismaintained under substantially constant external pressure, t-:on-t-inuousl'ypassing said reacting mass accompanied by carbon dioxide gas evolution through a pressure responsive restricted zone having a pressure responsivemovablemember, which member increases" and decreasesathe cross-sectional area of said zone inrepsonse to-variations-in pressure exertedtherein-by respective port-ion'sof s-aid reacting mass accompanied by' carbon dioxide gas evolution in the continuous passage thereof into and through said zone thereby to aid in effecting substantially uniform cell size in the foamed polyurethane plastic material ultimately produced, said cross-sectional area being transverse to the path of travel of said reacting mass through said zone.

5. A process for obtaining foamed polyurethane plastic material comprising the steps of 1) intimately admixing a plurality of reactants capable of reaction to produce polyurethane resin and carbon dioxide gas and (2) while a pressure responsive restricted zone is maintained under substantially constant external pressure, continuously passing the resulting reacting mass in which carbon dioxide gas is being produced into and through said pressure responsive restricted zone having a pressure responsive movable member, which member expands and contracts the cross-sectional area of said zone transverse to the path of travel of said reacting mass through said zone in response to pressure variations exerted therein by said reacting mass in the passage of said reacting mass through said zone thereby to aid in maintaining substantially uniform cell size in the foamed polyurethane plastic material ultimately produced, said reactants comprising a polyisocyanate and an organic compound having at least two reactable hydrogen atoms and capable of reacting with said polyisocyanate.

6. A continuous process for obtaining foamed polyurethane plastic materials comprising the steps of (1) intimately admixing a plurality of components capable of reacting together in the production of polyurethane resin and carbon dioxide gas thereby to initiate said reaction, (2) while a pressure responsive restricted zone is maintained under substantially constant external pressure, pass ing the resulting reacting mass into said pressure responsive restricted zone wherein reaction together with the production of carbon dioxide continues, said zone having a pressure responsive movable member, which member expands and contracts the cross-sectional area of said zone in response to pressure variations exerted therein between portions of said reacting mass passing into said zone thereby to aid in maintaining substantially uniform cell size in the ultimate foamed plastic material produced, and (3) presetting the cross-sectional area of said zone by varying the magnitude of said external substantially constant pressure applied externally to said zone while said reacting mass is passing through said expandable and contractable zone, thereby to aid in effecting a change in the substan tially uniform cell 'sizeof the foamed plastic material ultimately produced, said cross-sectional area being transverse to thepath of travel of said reacting mass through said zone, said components comprising a polyisocyanate and an organic compound having two reactable hydrogens and. cap-ableof reacting with said polyisocyanate.

7. In a method for continuously obtaining a foamed polyurethane resinous material, the step comprising while a pressure responsive restricted zone is; maintained under substantially constant external pressure, passing a'mixture of reactants, comprising a polyisocyanate and an organic compound having'two reactable hydrogens into and ,through said pressure responsive restricted zone wherein reaction occurs. between said reactants and carbon dioxide gas is evolved, said reactants being capable of reacting together in the course of ultimately produc ing said foamed polyurethan resinous material therefrom, said zone having a pressure responsive movable member, which member expands andcontracts said zone transversely of thevpath of travel ofsaid mass through said zone in responsive to pressure variations exerted therein by saidreacting mass in the course of the con-- tinuous passage therethrough of said reacting mass,- thereby to aid in eifecting substantially uniform cell siz e inthe foamed plastic material ultimately produced.

8. In a' method for continuously obtaining foamed polyurethane plastic material, the step comprising while a pressure responsive restricted zone is maintained under substantially constant external pressure, passing a reach; ing mass accompanied by carbon dioxide gas evolution into and through said zone in the course of said foamed polyurethane plastic material being ultimately produced therefrom, said zone having a pressure responsive movable member, which member expands and contracts the cross-sectional area of said zone in response to variations in pressure exerted therein by successive portions of said reacting mass accompanied by gas evolutions passing into and through said zone thereby to aid in maintaining substantially uniform cell size in successive portions of the foamed polyurethane plastic material thereafter ultimately produced fromrsaid reacting mass, said crosssectional area being transversev to the path of travel of said-reacting mass passing through said zone, said react-. ing mass accompanied by the evolution of carbon dioxide being produced in the course of reaction of a plurality of components capable of ultimately producing said foamed polyurethane plastic material, at least two of said components being (a) an organic polyisocyanate and (b) a compound capable of reacting with said polyisocyanatep H NITED STATES PATENTS I 2,764,565 Hoppe et a1. Sept. 25, 1956 2,885,268 Breer et al May 5, 1959 2,948,928 a .Ebneth et al. Aug. 16, 1960' i FOREIGN PATENTS 858,745 France May 20, 1940 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No, 219901380 June 27, 196].

Bertram J. Auerbach et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 7, for "in", second occurrence, read is column 5, line 2, for "so" read to line 29,

for continuuosly" read continuously column 7, line 48, for "that", firstoccurrence, read than column 9, line 22, for "discharge" read diaphragm column 10, lines 47 an 48, for "hydroxyls;" read hydroxyls: column 12, line 43, for "m-tolene" read m-toluene column 13, line 57, for "procedured" read produced column 15, line 20, for polyurethan" read polyurethane Signed and sealed this 5th day of December 1961.

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patent 

1. THE METHOD FOR PRODUCING FOAMED PLASTIC MATERIAL COMPRISING MIXING TOGETHER AN ORGANIC POLYISOCYANATE AND AN ORGANIC COMPOUND HAVING AT LEAST TWO REACTABLE HYDROGEN ATOMS AND CAPABLE OF REACTING WITH SAID POLYISOCYANATE WITH THE EVOLUTION OF CARBON DIOXIDE GAS FOR THE PRODUCTION OF SAID FOAMED PLASTIC MATERIAL AND PASSING THE RESULTING REACTING MASS ACCOMPANIED BY THE EVOLUTION OF CARBON DIOXIDE GAS INTO AND THROUGH A PRESSURE RESPONSIVE RESTRICTED ZONE WHEREIN REACTION ACCOMPANIED BY THE EVOLUTION OF CARBON DIOXIDE GAS CONTINUES TO OCCUR, SAID ZONE HAVING A PRESSURE RESPONSIVE MOVABLE MEMBER, WHICH MEMBER EXPAND AND CONTRACTS SAID ZONE IN RESPONSE TO PRESSURE VARIATIONS EXERTED THEREIN BY SUCCESSIVE PORTIONS OF SAID REACTING MASS PASSING THROUGH SAID ZONE THEREBY AIDING IN MAINTAINING SUBSTANTIALLY UNIFORM CELL SIZE IN THE ULTIMATE MATERIAL PRODUCED. 